/*******************************************************************************
 * Copyright (c) 2012-2015 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.ui.text.correction.proposals;

import org.eclipse.che.jdt.javaeditor.HasLinkedModel;
import org.eclipse.che.jface.text.ITextViewer;
import org.eclipse.che.jface.text.contentassist.ICompletionProposalExtension2;
import org.eclipse.che.jface.text.contentassist.ICompletionProposalExtension6;
import org.eclipse.che.jface.text.contentassist.IContextInformation;
import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.NodeFinder;
import org.eclipse.jdt.core.dom.SimpleName;
import org.eclipse.jdt.internal.corext.dom.LinkedNodeFinder;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.JavaPluginImages;
import org.eclipse.jdt.internal.ui.text.correction.AssistContext;
import org.eclipse.jdt.internal.ui.text.correction.CorrectionMessages;
import org.eclipse.jdt.internal.ui.text.correction.IProposalRelevance;
import org.eclipse.jdt.ui.SharedASTProvider;
import org.eclipse.jdt.ui.text.java.IInvocationContext;
import org.eclipse.jdt.ui.text.java.IJavaCompletionProposal;
import org.eclipse.jdt.ui.text.java.correction.ICommandAccess;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DocumentEvent;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.viewers.StyledString;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;

import java.util.Arrays;
import java.util.Comparator;

import static org.eclipse.che.plugin.java.server.dto.DtoServerImpls.LinkedModeModelImpl;
import static org.eclipse.che.plugin.java.server.dto.DtoServerImpls.LinkedPositionGroupImpl;
import static org.eclipse.che.plugin.java.server.dto.DtoServerImpls.RegionImpl;


/**
 * A template proposal.
 */
public class LinkedNamesAssistProposal
        implements IJavaCompletionProposal, ICompletionProposalExtension2, ICompletionProposalExtension6, ICommandAccess, HasLinkedModel {

//	/**
//	 * An exit policy that skips Backspace and Delete at the beginning and at the end
//	 * of a linked position, respectively.
//	 *
//	 * See https://bugs.eclipse.org/bugs/show_bug.cgi?id=183925 .
//	 */
//	public static class DeleteBlockingExitPolicy implements IExitPolicy {
//		private IDocument fDocument;
//
//		public DeleteBlockingExitPolicy(IDocument document) {
//			fDocument = document;
//		}
//
//		public ExitFlags doExit(LinkedModeModel model, VerifyEvent event, int offset, int length) {
//			if (length == 0 && (event.character == SWT.BS || event.character == SWT.DEL)) {
//				LinkedPosition position = model.findPosition(new LinkedPosition(fDocument, offset, 0, LinkedPositionGroup.NO_STOP));
//				if (position != null) {
//					if (event.character == SWT.BS) {
//						if (offset - 1 < position.getOffset()) {
//							//skip backspace at beginning of linked position
//							event.doit = false;
//						}
//					} else /* event.character == SWT.DEL */ {
//						if (offset + 1 > position.getOffset() + position.getLength()) {
//							//skip delete at end of linked position
//							event.doit = false;
//						}
//					}
//				}
//			}
//
//			return null; // don't change behavior
//		}
//	}


    public static final String ASSIST_ID = "org.eclipse.jdt.ui.correction.renameInFile.assist"; //$NON-NLS-1$

    private SimpleName          fNode;
    private IInvocationContext  fContext;
    private String              fLabel;
    private String              fValueSuggestion;
    private int                 fRelevance;
    private LinkedModeModelImpl linkedModel;

    public LinkedNamesAssistProposal(IInvocationContext context, SimpleName node) {
        this(CorrectionMessages.LinkedNamesAssistProposal_description, context, node, null);
    }

    public LinkedNamesAssistProposal(String label, IInvocationContext context, SimpleName node, String valueSuggestion) {
        fLabel = label;
        fNode = node;
        fContext = context;
        fValueSuggestion = valueSuggestion;
        fRelevance = IProposalRelevance.LINKED_NAMES_ASSIST;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#apply(org.eclipse.jface.text.ITextViewer, char, int, int)
     */
    public void apply(ITextViewer viewer, char trigger, int stateMask, int offset) {
        try {
            Point seletion = viewer.getSelectedRange();

            // get full ast
            CompilationUnit root = SharedASTProvider.getAST(fContext.getCompilationUnit(), SharedASTProvider.WAIT_YES, null);

            ASTNode nameNode = NodeFinder.perform(root, fNode.getStartPosition(), fNode.getLength());
            final int pos = fNode.getStartPosition();

            ASTNode[] sameNodes;
            if (nameNode instanceof SimpleName) {
                sameNodes = LinkedNodeFinder.findByNode(root, (SimpleName)nameNode);
            } else {
                sameNodes = new ASTNode[]{nameNode};
            }

            // sort for iteration order, starting with the node @ offset
            Arrays.sort(sameNodes, new Comparator<ASTNode>() {

                public int compare(ASTNode o1, ASTNode o2) {
                    return rank(o1) - rank(o2);
                }

                /**
                 * Returns the absolute rank of an <code>ASTNode</code>. Nodes
                 * preceding <code>offset</code> are ranked last.
                 *
                 * @param node the node to compute the rank for
                 * @return the rank of the node with respect to the invocation offset
                 */
                private int rank(ASTNode node) {
                    int relativeRank = node.getStartPosition() + node.getLength() - pos;
                    if (relativeRank < 0)
                        return Integer.MAX_VALUE + relativeRank;
                    else
                        return relativeRank;
                }

            });

            IDocument document = viewer.getDocument();
            LinkedPositionGroupImpl group = new LinkedPositionGroupImpl();
            for (int i = 0; i < sameNodes.length; i++) {
                ASTNode elem = sameNodes[i];
                RegionImpl region = new RegionImpl();
                region.setOffset(elem.getStartPosition());
                region.setLength(elem.getLength());
                group.addPositions(region);
//				group.addPosition(new LinkedPosition(document, elem.getStartPosition(), elem.getLength(), i));
            }

            LinkedModeModelImpl model = new LinkedModeModelImpl();
            model.addGroups(group);
//			model.forceInstall();
            model.setEscapePosition(offset);
            this.linkedModel = model;
            if (fContext instanceof AssistContext) {
//				IEditorPart editor = ((AssistContext)fContext).getEditor();
//				if (editor instanceof JavaEditor) {
//					model.addLinkingListener(new EditorHighlightingSynchronizer((JavaEditor)editor));
//				}
            }

//			LinkedModeUI ui = new EditorLinkedModeUI(model, viewer);
//			ui.setExitPolicy(new DeleteBlockingExitPolicy(document));
//			ui.setExitPosition(viewer, offset, 0, LinkedPositionGroup.NO_STOP);
//			ui.enter();

            if (fValueSuggestion != null) {
                document.replace(nameNode.getStartPosition(), nameNode.getLength(), fValueSuggestion);
//				IRegion selectedRegion = ui.getSelectedRegion();
//				seletion = new Point(selectedRegion.getOffset(), fValueSuggestion.length());
            }

//			viewer.setSelectedRange(seletion.x, seletion.y); // by default full word is selected, restore original selection

        } catch (BadLocationException e) {
            JavaPlugin.log(e);
        }
    }

    /*
     * @see ICompletionProposal#apply(IDocument)
     */
    public void apply(IDocument document) {
        // can't do anything
    }

    /*
     * @see ICompletionProposal#getSelection(IDocument)
     */
    public Point getSelection(IDocument document) {
        return null;
    }

    /*
     * @see ICompletionProposal#getAdditionalProposalInfo()
     */
    public String getAdditionalProposalInfo() {
        return CorrectionMessages.LinkedNamesAssistProposal_proposalinfo;
    }

    /*
     * @see ICompletionProposal#getDisplayString()
     */
    public String getDisplayString() {
//		String shortCutString = CorrectionCommandHandler.getShortCutString(getCommandId());
//		if (shortCutString != null) {
//			return Messages.format(CorrectionMessages.ChangeCorrectionProposal_name_with_shortcut, new String[]{fLabel, shortCutString});
//		}
        return fLabel;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension6#getStyledDisplayString()
     */
    public StyledString getStyledDisplayString() {
        StyledString str = new StyledString(fLabel);

//		String shortCutString = CorrectionCommandHandler.getShortCutString(getCommandId());
//		if (shortCutString != null) {
//			String decorated= Messages
//					.format(CorrectionMessages.ChangeCorrectionProposal_name_with_shortcut, new String[]{fLabel, shortCutString});
//			return StyledCellLabelProvider.styleDecoratedString(decorated, StyledString.QUALIFIER_STYLER, str);
//		}
        return str;
    }

    /*
     * @see ICompletionProposal#getImage()
     */
    public Image getImage() {
        return JavaPluginImages.get(JavaPluginImages.IMG_CORRECTION_LINKED_RENAME);
    }

    /*
     * @see ICompletionProposal#getContextInformation()
     */
    public IContextInformation getContextInformation() {
        return null;
    }

    /*
     * @see IJavaCompletionProposal#getRelevance()
     */
    public int getRelevance() {
        return fRelevance;
    }


    /* (non-Javadoc)
     * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#selected(org.eclipse.jface.text.ITextViewer, boolean)
     */
    public void selected(ITextViewer textViewer, boolean smartToggle) {
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#unselected(org.eclipse.jface.text.ITextViewer)
     */
    public void unselected(ITextViewer textViewer) {
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.text.contentassist.ICompletionProposalExtension2#validate(org.eclipse.jface.text.IDocument, int, org
     * .eclipse.jface.text.DocumentEvent)
     */
    public boolean validate(IDocument document, int offset, DocumentEvent event) {
        return false;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jdt.internal.ui.text.correction.IShortcutProposal#getProposalId()
     */
    public String getCommandId() {
        return ASSIST_ID;
    }

    public void setRelevance(int relevance) {
        fRelevance = relevance;
    }

    @Override
    public org.eclipse.che.ide.ext.java.shared.dto.LinkedModeModel getLinkedModel() {
        return linkedModel;
    }
}
